I've got a 32gig S9 on the way (literally being delivered in a truck) and I've got a few questions to help me prepare files before it gets here.

-After the flash drive is formatted, does it lose some disc space? Like how an 80gig harddrive is actually 74gigs after. (I guess it must, so my real question is how much space is left over for music and movies?)

-Does a full flash drive have problems like a full harddrive? That is, will I have to leave 3 gigs of empty space so that it'll run smoothly?

-Is defragging a flash drive okay? I know that defragging an ipod can be a bad idea since it'll heat the device up a lot, but considering flash is solid state? This is important since because of the limited space I will probably be switching music in and out, and I don't want wasted space because my drive is fragmented (ie if I can't defrag, I'll have to be very careful how I go about this).

-How long does the battery take to charge in a USB? I've heard Cowon products don't package a wall outlet. Will it drain power while I'm transferring files (should I worry about waiting for it to charge a little before I make a big transfer?)

1) Yes, your realistic storage space is about 30GB.
2) No, flash drives have no moving parts so there isn't a spindle turning when the OS is trying to find a file. It's lightning fast and can be accessed in the neighborhood of 100,000+ times before there's the possibility for disk fault.
3) SSD doesn't require defragmentation and is not recommended.
4) It took me in the neighborhood of 3 hours to fully charge my S9 via USB and yes it will drain the usual amount of power from the USB bus of your computer (I believe 500mA)

-No, but atleast on SSD's the performance goes down abit after a time(not noticeable on a PMP though).

-A flash drive benefits from being fragmented in a way, since read/writes will be more spread out, which means that the drive will live longer since each block has a number of times it can be addressed before they fail.

-About 1.5h if you start from "out of battery" IIRC. You'll be about 80% charged after 1h though.